Willy Wonka is the father of nano-food. The great chocolate- factory owner, you'll remember, invented a chewing gum that was a full three-course dinner. 'It will be the end of all kitchens and cooking,' he told the children on his tour - and produced a prototype sample of Wonka's Magic Chewing Gum. One strip of this would deliver tomato soup, roast beef with roast potatoes and blueberry pie and ice cream. In the right order. Violet Beauregarde snatched it, swiftly ate it and, at the pudding stage, turned bright purple and blew up to three times her size.

Far-fetched? The processed-food giant Kraft and a group of research laboratories are busy working towards 'programmable food'. One product they are working on is a colourless, tasteless drink that you, the consumer, will design after you've bought it. You'll decide what colour and flavour you'd like the drink to be, and what nutrients it will have in it, once you get home. You'll zap the product with a correctly-tuned microwave transmitter - presumably Kraft will sell you that, too.

This will activate nano-capsules - each one about 2,000 times smaller than the width of a hair - containing the necessary chemicals for your choice of drink: green-hued, blackcurrant-flavoured with a touch of caffeine and omega-3 oil, say. They will dissolve while all the other possible ingredients will pass unused through your body, in their nano-capsules.

The end of cooking? Probably not. Catch me having friends round for a programmable nanocola? Not more than once. But our reaction to some of the dafter promises of the new science is not really relevant. You may not want it, but the food industry does. Every major food corporation is investing in nano-tech - government in Europe has pumped £1.7 billion in research money into the field over the past eight years. Nano-food and nano-food packaging are on their way because the food industry has spotted the chance for huge profi ts: by 2010, the business, according to analysts, will be worth $20 billion annually. And there is already a prototype of a Wonka-esque chewing gum that, using nano-capsules, promises the sensation of eating real chocolate.

The food industry is hooked on nano-tech's promises, but it is also very nervous. At a conference in Amsterdam to discuss nano-technology, food and health, I found representatives of all the big food corporations, mixing with some bumptious academics, all thrilled with their latest nano-applications, and some less gung-ho bioethicists.

The food people included Unilever, Kraft, Cadbury Schweppes, Tate & Lyle and Glaxo-SmithKline: they were very shy and entirely off the record, if they spoke at all. I was having a friendly chat with a research scientist from Numico, the European baby-foods giant (their brands include Milupa and Cow & Gate) until he found out I was a journalist. Then he refused to tell me his name and asked me to erase the word 'Numico' from my notebook. I thought he was going to snatch it away. It's obvious why they were edgy. Consumers are not ready for nano-food. Among some scientists in the field there is a real sense that nano-technology, in food at least, is a revolution that may die in its cradle - rejected by a public that has lost its trust in scientists and its patience with industry's profi t-driven fooling with what we eat.

At the conference, the media was blamed, of course. The only journalist there, I got some eggs thrown at me. Ignorant, sensationalist journalism was holding back progress, fuelling the public's 'irrational' reaction to novel food processes. But Lynn Frewer, professor of food safety and consumer behaviour at Wageningen University, a leading centre of nano-tech research in the Netherlands, called the scientists to order. It was the public's irrational fears that needed addressing, she said: 'It's human nature. An involuntary risk, however remote, concerns people far more than one over which they have a choice. That's why the public find gene technology more threatening than eating fatty, unhealthy food.'

After the debates over GMO [genetically modified organisms] and BSE, she said, public faith is very low, not just in the food industry but also the food regulators. 'The mechanisms to make [them] transparent must be put in place and enshrined - there need to be principles that the public can understand.'

Dr David Bennett, a veteran biochemist now working on a European Commission project on the ethics of 'nanobiotechnology', felt the prospect was bleak. He thought public rejection of nanotechnology was 'almost certain'. 'Very little risk assessment has been done on this area, even on some products already entering the market - and it's an open question whether it will be done. To Greenpeace and Friends of the Earth, it's a gift.' And, he went on, the lack of proper assessment of nanotechnology 'scares me shitless'.

What's to be afraid of, from a technology that offers so much - healthier food, fewer, better targeted chemicals, less waste, 'smart' (and thus less) packaging, and even the promise of a technological solution to the problem of the one billion people who don't get enough to eat? Amid the papers on issues such as 'application of nano-filtration for demineralisation of twarog acid whey' (which will boost the yield in ice cream and yoghurt production) one much-discussed question in Amsterdam was how government should regulate the arrival of nano in the household. There are no new rules in Europe, and some voices - including the man from Unilever's research labs - dismissed the need for any. Nanotech is natural, he insisted: it uses no new substances, just the same ones smaller. But other scientists in the field disagree.

'Matter has different behaviour at nano-scales,' said Dr Kees Eijkel from the Dutch Twente University. 'That means diff erent risks are associated with it. We don't know what the risks are and the current regulations [on the introduction of new food processes] don't take that into account.'

Aluminium, for example, is stable in the 'big world' but an explosive at nano-levels. Some of the carbon nano-structures that are being used in electronics have been shown to be highly toxic if released into the environment. Some metals will kill bacteria at nano-scale - hence the interest in using them in food packaging - but what will happen if they get off the packaging and into us? No one seems to know - and as signifi cant a body as the UK's Royal Society has expressed worries over the lack of research into the health implications of free nano particles being introduced to our environment.

The size question is central to these concerns. Nano particles that are under 100 nano-meters wide - less than the size of a virus - have unique abilities. They can cross the body's natural barriers, entering into cells or through the liver into the bloodstream or even through the cell wall surrounding the brain.

'I'd like to drink a glass of water and know that the contents are going into my stomach and not into my lungs,' says Dr Qasim Chaudhry of the British government's Central Science Laboratory. 'We are giving very toxic chemicals the ability to cross cell membranes, to go where they've never gone before. Where will they end up? It has been shown that free nano-particles inhaled can go straight to the brain. There's lots of concerns. We have to ask - do the benefi ts outweigh the risks?'

Asbestos is the analogy everyone comes up with. Sixty years ago, the stable, cheap building material helped war-devastated Europe put up housing quickly, until it was discovered that asbestos micro-fi bres, once free, could cause hideous and lethal damage to the lungs.

Dr Chaudhry has been leading a team of researchers reporting to the government's Food Standards Agency on nanotechnology and safety. He is worried that the health research is way behind the technology and that a whole range of tests has not been carried out - for instance, on the nano-compounds already being tested for water cleaning in Third World countries. Dr Chaudry's team has told the Department of Environment, Food and Rural Aff airs that it thought companies and researchers introducing nanoproducts should be obliged to notify the authorities about them. DEFRA agreed and launched the list scheme in September, but decided notification should be voluntary, not mandatory. And you and I cannot see the list - it will, out of respect to commercial interests, be kept secret.

This doesn't sound like the sort of openness that will soothe a concerned public, all too wary nowadays of the reassurances of the food industry and science . But the FSA, which is awaiting the results next year of two research projects into nano-tech, food and safety, says it is confident that existing regulations on 'novel' foods, additives and food processes will cover any new products. And, at the moment, it doesn't believe there is any nano-tech in food in Britain - though some scientists think that is wrong.

As with GM, we may be overtaken by events in the States, where food regulators have, under the Bush presidency, been steam-rollered by a food industry eager to push in the new technology. So far, however, the list of kitchen nano-products actually on American shelves is unimpressive. The Woodrow Wilson Center, a Washington research institute, runs a database of nano-tech products that are commercially available, and the list under Food and Beverage is only 29 products long, compared with 201 under Health and Fitness (I'm excited by the nano-silverised self-cleaning socks). But the list has grown 50 per cent since March, when it was only 19 products long.

Most of these products are self-cleaning and anti-bacterial food-packaging items : cutting boards and so on. There's a couple of Samsung nano-silverised refrigerators. There are nutritional supplements, under the well-established American brand Nanoceuticals. There's a Vitamin B12 spray marketed by Nutrition-by-Nanotech. You simply catch a child with an open mouth and spray the stuff straight in: they'll absorb the nano-sized vitamins directly through the mucal cells. 'Tastes like candy... Would you believe it, they are asking for more!' runs the copy line, less than enticingly.

Only three items on the Woodrow Wilson list are listed as food. One is 'Nanotea', from a Chinese company, that will increase tenfold the amount of selenium absorbed from green tea (that's a good thing), through capsules engineered to bypass the stomach and dissolve in your lower gut. There's Canola Activa Oil, an Israeli invention: nano-capsule-delivered chemicals in rapeseed cooking oil that will stop cholesterol entering the bloodstream - this is exciting technology, utilising nano's ability to suspend or dissolve any substance you like in water or in oil. And fi nally there's SlimShake chocolate - a powdered drink that uses nanotechnology to cluster the cocoa cells, and thus cut out the need for sugar.

More important, what of the promise that nanotechnology offers hope to the one billion habitually undernourished on the planet? Nothing yet. Dr Donald Bruce, a chemist who heads a group examining technology and ethics for the Church of Scotland, is doubtful. He sat on a committee 10 years ago examining the moral implications of the introduction of GM. 'The public were told that genetic modifi cation was going to feed the world. And so we looked for evidence of any application of that science that had addressed the needs of a poor subsistence farmer. We couldn't fi nd any. The industry went for agronomic benefits, not for people benefits.'

With nano-tech, the food industry has once again got it back to front, he feels. ' Such innovation must be consumer-led - the consumer must be able to see what's in it for them.' Violet Beauregarde would certainly agree.

Arrival of the nano state Self-cleaning fridges, turning red wine into white - the future's tiny

What is it?

Tiny technology with big results Nanotechnology is the science of the tiny - the precision engineering of substances at molecular and atomic level. The scale is amazingly small. A nanometer is a billionth of a meter: the width of a human hair is 80,000 nanometers and this industry is manufacturing complex nanomaterials 30 nm wide or less.

The industry exploits the fact that physics and chemistry change at nano-scale and common substances behave very diff erently - thus many of the metals and chemicals that industry works with take on startling new properties. 'It's like having a brand new tool box,' says one enthusiastic scientist. The uses these tools can be put to are amazing but, like any only partially explored and tested technology, potentially dangerous. Nanotech is all around you, already: in clothing, electronics, manufacturing and increasingly in health and cosmetics. If you buy a clear sunscreen that promises it blocks ultraviolet light, it is using nano-particles of metals like zinc or titanium - it's clear because the particles are too small to aff ect ordinary light. L'Oreal (backed by the food company Nestlé) is marketing anti-ageing cosmetics that exploit the tininess of the particles, 'nanosomes', and their ability to penetrate deep into skin cells.

Nano in the kitchen

Bacteria-bashing and choice of colour As yet there are officially no foods on sale in Europe that contain nanomaterials, though they exist in the States. But regulation is very light and food, along with health products, are high on an excited industry's target list - that's where big money is.

Nano-packaging with 'self-cleaning' abilities will be the first application you'll see - but the science behind that isn't very different from that in the 'anti-bacterial' food containers on sale now. It is with nano-engineered food ingredients that things get mind-boggling. Just arriving are techniques that will turn established food chemistry and processing upside-down. Precisely- engineered nano-scale filters allow you to remove all bacteria from milk or water without boiling. Or take the red out of red wine. Water into oil doesn't go? Nano-encapsulation technology can already allow you to dissolve as much oil in water, and the other way round, as you wish. It does this by encasing the water or oil molecules individually in capsules that the liquid will accept. This has enormous implications for altering the fats and salt content of our foods. For cooks, it will turn sauce-making on its head, allowing the emulsifi cation of any two liquids - just for starters, that's a vinaigrette you won't have to stir together before pouring. The nanocapsules, 2,000 times narrower than a hair, allow the suspension of almost any substance in clear liquids, without altering their look, or giving any taste.

Nano-delivery systems are already making feeding via our stomach out of date: nano-encapsulation can deliver nutrients - and anything else - through the mucal walls in your mouth, or your nose or via your lower gut. This is scary, though useful: many nutrients are destroyed or wasted by the digestive process; releasing them later is a way of ensuring that much more of the substance enters the bloodstream. Already nano-capsule cases are being made that are resistant to stomach acid but can be broken down further on in the digestive process, say, by the bacteria in the colon.

Nano researchers talk of being able ultimately to design nano-capsule delivery systems that will take any substance to any part of the body. In the kitchen, the promise is that, with microbiochemistry and nanotechnology, chefs will one day be able to pin down tastes, textures and colours and deliver them to order. They will be able to design dishes at molecular level and build the food that you receive on your plate just as a composer chooses the notes that an orchestra plays. Heston Blumenthal should relax, though - that's a long way ahead.

Nano now

Chocolate-flavoured chewing gum, milk that tells you when it's off Thanks to nano-encapsulation (see above), some truly Willy Wonka-ish nano products are on their way. An American company has claimed to have created 'the Holy Grail of chewing-gum design' - chewing gum with real chocolate in it. Hazelnut-cappucino fl avour is next. You'll first meet nanotechnology in food packaging. Most people have heard about the 'smart' food packaging that will warn when oxygen has got inside, or if food is going off - research on that is complete and the products are arriving.

Samsung has fridges on the market in Asia and America that use nano-silver to kill bacteria. Already in use in brewing and dairy production are nano-filters - screens so small they can fi lter out micro-organisms and even viruses. In lab experiments, the colour has been removed from beetroot juice, leaving the fl avour; and red wine turned into white. Lactose can now be filtered from milk, and replaced with another sugar - making all milk suitable for the lactose-intolerant. This could mean less use of chemicals and heat treatments in food processing.

Also available in American supermarkets is cooking oil that, in theory, can be kept fresh and soluble forever - thanks to nano-ceramic particles that enable clustering of dirt molecules. Nano-engineered molecules, which lock onto contaminants, will simplify the process of cleaning drinking water - potentially hugely important for the developing world. Parents are a big market for nano, obviously. Nano-encapsulation means no more bribing your kids to eat fruit and oily fish: vitamin C-enriched cooking oil and omega-3 fi sh oil-carrying juices are already available. In Australia, you can buy a bread - Tip-Top - that contains undetectable nano-capsules of omega-3.

Nano soon

Teeth cleaning chewing gum, self-cleaning cutlery

Fancy a programmable drink? Beverage companies such as Kraft are working on prototypes of soft drinks containing nano-capsules that will carry a range of fl avours, colours, preservatives or nutrients. You buy the drink and then choose which elements to activate. Your milk carton will tell you when its contents are sour, thanks to particles that sense the gases of decomposition and change colour, and nano-molecules in the ink on the label that tell you how old it is and duly change colour. Kraft and Unilever have products on test.

The food industry is excited about sell-by dates and self-preserving food. Nano-coatings will make the life span of manufactured food even longer. Mars has a US patent for nano-scale fi lms that have been tested on M&Ms, Twix and Skittles. The coatings are made from oxides of silicon or titanium, are undetectable, could kill bacteria, and would increase the life of many manufactured foods, even after they are opened.

Packaging that absorbs oxygen, making food last longer, is on its way. Kodak already has it in development for photographic film. Food manufacturers including Unilever and Nestlé plan to use nano-encapsulation to improve shelf life and engineer taste sensations in fat-based foods like chocolates, ice creams and spreads. There could be huge reductions in fats and salts in processed foods. Unilever believes it can reduce the fat content of ice cream from 15 per cent to one per cent.

When it comes to chewing gum, nano-particles will shortly be able to carry teeth-cleaning chemicals that you won't be able to taste. Pleasing to the lazy, as will be self-cleansing cutlery, an advance made possible by the engineering, at atomic level, of hydrophobic surfaces that allow substances to break down and drop off . This is already in use with industrial glass products. Nano-fi lters will allow you to choose the amount of caffeine you want to remove from your coff ee. Making tap water sterile should be possible too.

Nano-scale sensors are in development that will monitor toxins and bacteria at all stages of food processing. This will help producers spot salmonella in chickens, or E-coli in spinach, long before the products reach the shops. Self-monitoring food packaging will mature into technology like the nano-tongue. Wired into your fridge, it will detect and warn you of a whole range of chemicals given off by rotting food, or the presence of bacteria. And then clean them.

Nano in the future

Interactive chicken, nano-noses

Atomic-level encapsulation techniques will get more sophisticated. Food processors will offer engineered food catering to your specific tastes, and all sort of options to shoppers. If your chicken is going to sit in the fridge for a while, just activate the nano-encapsulated preservatives held dormant in its flesh. Fancy a fillet with a tarragon-and-butter taste? Trigger a different nano-capsule. Nano-encapsulation could let chefs choose, exactly, how strong a taste or smell should be and when it should be delivered, and design a food's mouth-feel. The capsule's casing is to be made of substances ranging from starches, proteins and fats, and can be tailored to break down and release its contents to order.

A chef might decide that some flavours in his dish would only be released to the eater a certain number of seconds or minutes after chewing, or when they sip a glass of wine. Another nano-system to excite cooks uses stable molecules to tie down volatile ones: manufactured starch such as cyclodextrin is being used to bond to those frustratingly evanescent fl avours in food - like the fast-fading taste of dill, for example. The perfume industry is already using this to make scents perform longer.

Go food shopping, or out to a restaurant, and you could carry your own nano-nose, a personal tasting sensor programmed to test food for things you don't like, or chemicals and allergens which may make you ill. Meanwhile, nano-sized bar codes will enable random molecules of an animal's meat to be tagged and monitored from farm to every end product.

Further ahead, the industry is looking at food that is pre-engineered to cater for your tastes, your dislikes and your allergies. Or just built from scratch. Ultimately, says Franz Kampers, a scientist at the Netherland's Wageningen University, 'The Holy Grail of the food industry is to create something like this' - he shows a picture of a glistening roast turkey with all the trimmings - 'from plant protein. That would be really something!'. You may not want it, but the scientists are already halfway there.